1. Field of the Invention
The present invention relates to a semiconductor integrated circuit device.
2. Description of the Prior Art
In general, a semiconductor integrated circuit device has a plurality of leads provided in an edge portion of the package thereof so as to project therefrom for connection to a printed circuit board.
On the other hand, a semiconductor integrated circuit device has an integrated circuit chip enclosed in a central portion of the package thereof, and the chip has a plurality of bonding pads provided thereon that are connected individually to the leads of the package by wire bonding. That is, input and output of signals to and from the internal circuit of the chip is achieved by way of bonding pads corresponding to the individual signals.
However, the signals input to and output from the internal circuit have different amplitudes from one another, and therefore, when wires are bonded, it is necessary to select appropriate leads to prevent two signals having greatly different amplitudes from being input or output by way of leads too close to each other. This helps alleviate problems such as crosstalk, but with limited result in exchange for much inconvenience.
Such a chip can be enclosed also in a package of a BGA (ball grid array) type. In the case, the signals corresponding to the bonding pads provided on the chip is input thereto or output therefrom by way of solder pads from or to the bonding pads provided on the package.
If the two signals are transferred by way of two solder pads that are too close to each other, problems such as crosstalk occur; moreover, also on the part of the printed circuit board on which the BGA package is mounted, problems occur with the conductive patterns that are laid so as to be connected individually to those two solder pads. Such problems can be avoided by assigning the above-mentioned two signals to different bonding pads, but this requires modification of the masking pattern of the chip, and thus cannot be achieved readily.